The present invention relates generally to elastomer-tipped metallic devices such as armatures, needle valves and the like and, more particularly, to an improved composite construction thereof.
Elastomer-tipped metallic devices in a wide variety of configurations are currently used as plungers or armatures for electric solenoid assemblies and as needle valves in a diverse variety of applications. A typical device has a solid or tubular metal body with a cavity or seat formed in one end and a resilient elastomer tip molded or bonded in the cavity at the body end and projecting outwardly therefrom. The elastomer tip can provide a seal which eliminates leakage of fluids, can be an interface component which eliminates wear of other components and reduces impact noise levels, and is abrasion and impact resistant and compatible with a wide variety of fluids.
To be capable of operating satisfactorily in diverse applications such as sealing and controlling the flow of fuels, water, air, vacuum and refrigerant, these devices must meet extremely stringent design specifications in terms of precision and fine tolerances. At the same time, these devices are used worldwide and produced in the millions of units. Thus, the manufacturability of the devices is a major consideration. One conventional manufacturing process basically involves, first, fabricating the metal body. Next, the metal body is placed in a mold and the elastomer tip is molded and bonded onto one end of the body. Then, the rubber tip is ground to the configuration and fine tolerances desired.
While the above-described conventional manufacturing process has been successful over the years in producing devices in the large numbers and to the stringent design standards required, there is a continuing need to find a more simplified approach to the manufacture of such devices, while retaining the extremely high tolerances necessary for their successful operation.